Parse Python code and perform AST validation.
"""
import ast
-import platform
import sys
-from typing import Any, Iterable, Iterator, List, Set, Tuple, Type, Union
-
-if sys.version_info < (3, 8):
- from typing_extensions import Final
-else:
- from typing import Final
+from typing import Final, Iterable, Iterator, List, Set, Tuple
from black.mode import VERSION_TO_FEATURES, Feature, TargetVersion, supports_feature
from black.nodes import syms
from blib2to3.pgen2.tokenize import TokenError
from blib2to3.pytree import Leaf, Node
-ast3: Any
-
-_IS_PYPY = platform.python_implementation() == "PyPy"
-
-try:
- from typed_ast import ast3
-except ImportError:
- if sys.version_info < (3, 8) and not _IS_PYPY:
- print(
- (
- "The typed_ast package is required but not installed.\n"
- "You can upgrade to Python 3.8+ or install typed_ast with\n"
- "`python3 -m pip install typed-ast`."
- ),
- file=sys.stderr,
- )
- sys.exit(1)
- else:
- ast3 = ast
-
-
PY2_HINT: Final = "Python 2 support was removed in version 22.0."
def parse_single_version(
- src: str, version: Tuple[int, int]
-) -> Union[ast.AST, ast3.AST]:
+ src: str, version: Tuple[int, int], *, type_comments: bool
+) -> ast.AST:
filename = "<unknown>"
- # typed-ast is needed because of feature version limitations in the builtin ast 3.8>
- if sys.version_info >= (3, 8) and version >= (3,):
- return ast.parse(src, filename, feature_version=version, type_comments=True)
-
- if _IS_PYPY:
- # PyPy 3.7 doesn't support type comment tracking which is not ideal, but there's
- # not much we can do as typed-ast won't work either.
- if sys.version_info >= (3, 8):
- return ast3.parse(src, filename, type_comments=True)
- else:
- return ast3.parse(src, filename)
- else:
- # Typed-ast is guaranteed to be used here and automatically tracks type
- # comments separately.
- return ast3.parse(src, filename, feature_version=version[1])
+ return ast.parse(
+ src, filename, feature_version=version, type_comments=type_comments
+ )
-def parse_ast(src: str) -> Union[ast.AST, ast3.AST]:
+def parse_ast(src: str) -> ast.AST:
# TODO: support Python 4+ ;)
versions = [(3, minor) for minor in range(3, sys.version_info[1] + 1)]
first_error = ""
for version in sorted(versions, reverse=True):
try:
- return parse_single_version(src, version)
+ return parse_single_version(src, version, type_comments=True)
except SyntaxError as e:
if not first_error:
first_error = str(e)
- raise SyntaxError(first_error)
-
+ # Try to parse without type comments
+ for version in sorted(versions, reverse=True):
+ try:
+ return parse_single_version(src, version, type_comments=False)
+ except SyntaxError:
+ pass
-ast3_AST: Final[Type[ast3.AST]] = ast3.AST
+ raise SyntaxError(first_error)
def _normalize(lineend: str, value: str) -> str:
return normalized.strip()
-def stringify_ast(node: Union[ast.AST, ast3.AST], depth: int = 0) -> Iterator[str]:
+def stringify_ast(node: ast.AST, depth: int = 0) -> Iterator[str]:
"""Simple visitor generating strings to compare ASTs by content."""
- node = fixup_ast_constants(node)
+ if (
+ isinstance(node, ast.Constant)
+ and isinstance(node.value, str)
+ and node.kind == "u"
+ ):
+ # It's a quirk of history that we strip the u prefix over here. We used to
+ # rewrite the AST nodes for Python version compatibility and we never copied
+ # over the kind
+ node.kind = None
yield f"{' ' * depth}{node.__class__.__name__}("
- type_ignore_classes: Tuple[Type[Any], ...]
for field in sorted(node._fields): # noqa: F402
- # TypeIgnore will not be present using pypy < 3.8, so need for this
- if not (_IS_PYPY and sys.version_info < (3, 8)):
- # TypeIgnore has only one field 'lineno' which breaks this comparison
- type_ignore_classes = (ast3.TypeIgnore,)
- if sys.version_info >= (3, 8):
- type_ignore_classes += (ast.TypeIgnore,)
- if isinstance(node, type_ignore_classes):
- break
+ # TypeIgnore has only one field 'lineno' which breaks this comparison
+ if isinstance(node, ast.TypeIgnore):
+ break
try:
value: object = getattr(node, field)
# parentheses and they change the AST.
if (
field == "targets"
- and isinstance(node, (ast.Delete, ast3.Delete))
- and isinstance(item, (ast.Tuple, ast3.Tuple))
+ and isinstance(node, ast.Delete)
+ and isinstance(item, ast.Tuple)
):
for elt in item.elts:
yield from stringify_ast(elt, depth + 2)
- elif isinstance(item, (ast.AST, ast3.AST)):
+ elif isinstance(item, ast.AST):
yield from stringify_ast(item, depth + 2)
- # Note that we are referencing the typed-ast ASTs via global variables and not
- # direct module attribute accesses because that breaks mypyc. It's probably
- # something to do with the ast3 variables being marked as Any leading
- # mypy to think this branch is always taken, leaving the rest of the code
- # unanalyzed. Tighting up the types for the typed-ast AST types avoids the
- # mypyc crash.
- elif isinstance(value, (ast.AST, ast3_AST)):
+ elif isinstance(value, ast.AST):
yield from stringify_ast(value, depth + 2)
else:
yield f"{' ' * (depth+2)}{normalized!r}, # {value.__class__.__name__}"
yield f"{' ' * depth}) # /{node.__class__.__name__}"
-
-
-def fixup_ast_constants(node: Union[ast.AST, ast3.AST]) -> Union[ast.AST, ast3.AST]:
- """Map ast nodes deprecated in 3.8 to Constant."""
- if isinstance(node, (ast.Str, ast3.Str, ast.Bytes, ast3.Bytes)):
- return ast.Constant(value=node.s)
-
- if isinstance(node, (ast.Num, ast3.Num)):
- return ast.Constant(value=node.n)
-
- if isinstance(node, (ast.NameConstant, ast3.NameConstant)):
- return ast.Constant(value=node.value)
-
- return node
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